<!DOCTYPE html>
<html>
  <head>
  <style>
    .box {
      width: 100px;
      height: 100px;
      margin: 10px;
      border-width: 20px;
      border-color: black;
      border-style: solid;
    }
  </style>
  </head>
<body>
  <!-- Test mixed border styles. Expect a square with solid dark border.
    -->
  <div class="box"></div>
</body>
</html>
